plastid

Presented By:
Fatima Adil
Roll No:
18371514-106
Presented To:
Sir Tahir Iqbal


 Plastids are double membrane bound organelles.
 Found inside plants and algae.
 Responsible for activities related to manufacture and
storage of important chemical compounds used by the
cells .
 The types of pigments present can
determine the cell's color.
INTRODUCTION


 Pro-plastids may develop into of the following:
 Chloroplasts
 Chromoplasts
 Leucoplasts
TYPES OF PLASTIDS


CHLOROPLAST
 The chloroplasts are probably the most known of the
plastids.
 These are responsible for photosynthesis.
 Found in plant cells and other eukaryotic organisms.
 The word chloroplast is derived from the Greek words
 Chloros, which means green,
 Plast, which means entity


 Chloroplast are spheroid or ovoid or discoid in higher
plants.
 Bounded by a double membrane called the chloroplast
envelope.
 Chloroplasts have a third internal membrane system,
called the thylakoid membrane.
 Thylakoid membrane forms a network of flattened discs
called thylakoids, arranged in stacks called grana.
General structure:


 Chromoplasts are place for the pigments to be stored and
synthesized in the plant.
 Found in flowering plants, fruits, and aging leaves.
 Chloroplasts actually convert over to chromoplasts.
 There are carotenoid pigments here that allow for the
different colors.
CHROMOPLASTS


 Based on structure, chromoplast are categorized as
follow:
 Globular chromoplasts
 Crystalline chromoplasts
 Fibrillar chromoplasts
 Tubular chromoplasts
 Membranous chromoplasts.
Categories of chromoplast:


 There are two types of chromoplasts which include:
 Phaeoplast
• Brownish and naturally found in brown algae
 Rhodoplast
• Plastids found in red algae
Types of chromoplast:


 Leucoplasts are the non-pigmented organelles.
 Leucoplasts have no color at all.
 Found in the non-photosynthetic
parts of the plants,
• such as the roots.
 Used for synthesizing amino acids
and fatty acids.
LEUCOPLASTS


 Leucoplasts are further subdivided into three different
plastids:
 Amyloplasts
• are the largest of the three and are charged with storing starch.
 Proteinoplasts
• help to store the proteins that a plant needs and are typically
found in seeds.
 Elaioplasts
• are used to store fats and oils that are needed by the plant,
specifically in seeds.
Types of leucoplasts:


 Number of plastids range from 30 to 40 and 100 to 150 in
diploid cells.
 The plastids of plants are also simpler when compared to
those found in other organisms like algae.
 Depending on the species plastids take up a variety of
shapes
• e.g. discoid, spherical, dumbbell-shaped or lens-shaped
among a few others.
General Structure and Features of Plastids:


 One of the other important structures associated with
plastids is the stromule.
 Stromule plays an important role in ensuring
communication between the plastids and other cell
organelles
• such as the mitochondria and the cell nucleus.


 Double membrane is only membrane that remains intact.
 Due to genome reduction of plastids, they are only able to
encode for a small number of proteins.
 The membrane, plays an important role in
• Cell signaling
• Regulation of gene expression.
Double-Membrane


 Some of the other roles of plastid envelopes include:
 Transport of other material including vital metals and
metabolites
 Metabolism of fatty acid, lipids, and carotenoid among
other compounds
 Production of plant growth regulators
 Interaction with the cell's endomembrane systems
Cntd..


 Stroma refers to the internal space that is enclosed by the
double membrane of the plastid.
 Some of the other components of the stroma include:
 Ribosome -
• Is a major characteristic of plastid stroma.
• The presence of ribosome indicates protein synthesis
activities.
PLASTID STOMA


 Nucleoids –
• Include copies of the plastid DNA and RNA.
• Functional unit of the plastid's genome..
 Other components found in the stroma include:
 Inclusion bodies
 Microtubules
 Stromacenters
 Starch
 Plastoglobuli
Cntd..


 Found in land plants.
 Develops from the inner membrane envelope.
 Attach to the inner membrane forming a membrane system
known as the peripheral reticulum.
 This system plays role in the transport of materials from
the cytoplasm to plastid and vice versa.
INTERNAL MEMBRANE

plastid

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